[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 8 commits: Make typechecker equality consider visibility in ForAllTys

Sat Oct 31 07:26:53 UTC 2020

 Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC

Commits:
57c3db96 by Ryan Scott at 2020-10-31T02:53:55-04:00
Make typechecker equality consider visibility in ForAllTys

Previously, `can_eq_nc'` would equate `ForAllTy`s regardless of their
`ArgFlag`, including `forall i -> i -> Type` and `forall i. i -> Type`! To fix
this, `can_eq_nc'` now uses the `sameVis` function to first check if the
`ArgFlag`s are equal modulo specificity. I have also updated `tcEqType`'s
implementation to match this behavior. For more explanation on the "modulo
specificity" part, see the new `Note [ForAllTy and typechecker equality]`
in `GHC.Tc.Solver.Canonical`.

While I was in town, I fixed some related documentation issues:

* I added `Note [Typechecker equality]` to `GHC.Tc.Utils.TcType` to describe
  what exactly distinguishes `can_eq_nc'` and `tcEqType` (which implement
  typechecker equality) from `eqType` (which implements definitional equality,
  which does not care about the `ArgFlags` of `ForAllTy`s at all).
* The User's Guide had some outdated prose on the specified/inferred
  distinction being different for types and kinds, a holdover from #15079. This
  is no longer the case on today's GHC, so I removed this prose, added some new
  prose to take its place, and added a regression test for the programs in
  #15079.
* The User's Guide had some _more_ outdated prose on inferred type variables
  not being allowed in `default` type signatures for class methods, which is no
  longer true as of the resolution of #18432.
* The related `Note [Deferred Unification]` was being referenced as
  `Note [Deferred unification]` elsewhere, which made it harder to `grep`
  for. I decided to change the name of the Note to `Deferred unification`
  for consistency with the capitalization style used for most other Notes.

Fixes #18863.

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a98593f0 by Sylvain Henry at 2020-10-31T02:54:34-04:00
Refactor numeric constant folding rules

Avoid the use of global pattern synonyms.

1) I think it's going to be helpful to implement constant folding for
   other numeric types, especially Natural which doesn't have a wrapping
   behavior. We'll have to refactor these rules even more so we'd better
   make them less cryptic.

2) It should also be slightly faster because global pattern synonyms
   matched operations for every numeric types instead of the current one:
   e.g., ":**:" pattern was matching multiplication for both Int# and
   Word# types. As we will probably want to implement constant folding
   for other numeric types (Int8#, Int16#, etc.), it is more efficient
   to only match primops for a given type as we do now.

- - - - -
730ef38f by Sylvain Henry at 2020-10-31T02:54:34-04:00
Simplify constant-folding (#18032)

See #18032 for the details.

* Use `Lit (LitNumber _ i)` instead of `isLitValue_maybe` which does
  more work but that is not needed for constant-folding
* Don't export `GHC.Types.Literal.isLitValue_maybe`
* Kill `GHC.Types.Literal.isLitValue` which isn't used

- - - - -
d5a53c1a by Ben Gamari at 2020-10-31T02:55:10-04:00
primops.txt.pp: Move ByteArray# primops to separate file

This file will be generated.

- - - - -
b4278a41 by Ben Gamari at 2020-10-31T02:55:10-04:00
primops: Generate ByteArray# index/read/write primops

Previously these were mostly undocumented and was ripe for potential
inconsistencies.

- - - - -
08e6993a by Sylvain Henry at 2020-10-31T02:55:50-04:00
Move loadDecl into IfaceToCore

- - - - -
459a8534 by Tamar Christina at 2020-10-31T03:26:45-04:00
winio: Fix unused variables warnings

- - - - -
926c9e35 by Andrzej Rybczak at 2020-10-31T03:26:47-04:00
Add testcase for #816

- - - - -

30 changed files:

- + compiler/GHC/Builtin/bytearray-ops.txt.pp
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Iface/Load.hs
- compiler/GHC/Iface/Syntax.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/IfaceToCore.hs-boot
- compiler/GHC/Tc/Solver/Canonical.hs
- compiler/GHC/Tc/Utils/TcType.hs
- compiler/GHC/Tc/Utils/Unify.hs
- compiler/GHC/Types/Literal.hs
- compiler/GHC/Types/TyThing.hs
- docs/users_guide/exts/poly_kinds.rst
- docs/users_guide/exts/type_applications.rst
- libraries/base/GHC/Event/Windows.hsc
- rts/win32/AsyncWinIO.c
- rts/win32/AsyncWinIO.h
- + testsuite/tests/saks/should_fail/T18863a.hs
- + testsuite/tests/saks/should_fail/T18863a.stderr
- + testsuite/tests/saks/should_fail/T18863b.hs
- + testsuite/tests/saks/should_fail/T18863b.stderr
- testsuite/tests/saks/should_fail/all.T
- + testsuite/tests/simplCore/should_run/NumConstantFolding.hs
- + testsuite/tests/simplCore/should_run/NumConstantFolding.stdout
- testsuite/tests/simplCore/should_run/all.T
- + testsuite/tests/typecheck/should_compile/T15079.hs
- + testsuite/tests/typecheck/should_compile/T816.hs
- testsuite/tests/typecheck/should_compile/all.T

The diff was not included because it is too large.

View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5b3972b563c8b871c424ad703daa4c4322b673a8...926c9e3595cc7d48400cecfb4482388b5dd8df4a

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/5b3972b563c8b871c424ad703daa4c4322b673a8...926c9e3595cc7d48400cecfb4482388b5dd8df4a
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